om500320t_si_001.pdf (959.24 kB)
Iridium-Promoted Conversion of Chlorosilanes to Alkynyl Derivatives in a One-Pot Reaction Sequence
journal contribution
posted on 2014-06-23, 00:00 authored by Ireneusz Kownacki, Bartosz Orwat, Bogdan MarciniecBy making use of the catalytic potential
of the iridium system
[{Ir(μ-Cl)(CO)2}2]/NEt(i-Pr)2 in the synthesis of silyl-functionalized alkynes
via silylative coupling of terminal alkynes/diynes with iodosilanes,
we propose a new protocol allowing employment of various mono- and
dichlorosilanes as reagents. The process is based on a sequence of
two reactions occurring simultaneously: i.e., conversion of initial
chlorosilane (SiR1nCl4–n) to the appropriate iodosilane via Cl/I nucleophilic
substitution and its further conversion to a silylalkyne derivative
((SiR1n(CCR2)4–n) via iridium-catalyzed silylative
coupling with terminal alkyne. Under optimum conditions, the method
has proved to be effective and versatile in the conversion of a wide
range of chlorosilanes to a rich portfolio of various corresponding
alkynyl-functionalized silicon derivatives. Additionally, NMR studies
of the equimolar reaction of a well-defined iridium(I) alkynyl precursor
with Me3Si–I revealed that Si–I bond
activation in iodosilane molecules occurred via oxidative addition
to the iridium center.